1. Field of the Invention
The present invention relates to composite laminates and, more particularly, to a heat deformable composite laminate and a process for making such laminates.
2. Description of the Prior Art
In the past, it has been customary to thermoform certain objects for use in displays and packaging, for example, contoured supports for pen and pencil sets in containers, from paper or plastic material generally in the form of a sheet. In the case of ordinary plastic materials, the process could often be done merely by vacuum forming.
In order to impart a more luxurious appearance and feel to the supporting material as well as to meet the needs of special applications such as preparing the panels or lining of musical instrument cases, the article contacting surface of supports is sometimes coated, such as by flocking or by the application of a separate layer of soft material such as felt. The difficulty of flocking or of applying a layer to the surface of such an article in its contoured form will be readily apparent to those skilled in the art, and manufacturers in the past have experienced a number of problems with this process.
Important features of the resulting article are uniformity of appearance and cushioning ability. It is difficult to impart a uniform appearance to the resulting article since the adherence of the fiber flock of the applied layer is often uneven and irregular when flocking is accomplished on the contoured surface. Another defect experienced with these previous methods has been the lack of sufficient cushioning afforded by the known structures employed for the above purpose. This appears to be due to an inherent limitation in the length of the fibers of the flock material as well as the inherent inability of these fibers alone to provide adequate softness or cushioning. The above problems are especially significant where this material is used as lining in carrying cases for musical instruments. Here, ability to cushion and protect the instrument becomes extremely important along with uniformity of appearance.
Ordinarily a flock surfacing is produced by a random distribution of fibrous material, of any preferred type and dimensions, over a layer of adhesive which has been applied to the particular substrate. The loading of fibrous material will determine, to a major extent, the density of the resultant surface although, in some instances, orientation of the fibrous material in a plane normal to that of the substrate through an electrical or electrostatic field or by exposure to mechanical oscillation as is so well known to the art will contribute depth to the surface stratum since only a terminal bonding of the individual fibers of the flock ensues.
But in these usual circumstances the adhesive layer must be relatively thick in order that adequate contact with the fibers will be possible and there will customarily be generated an impermeable membrane which not only unites the elements of the substrate but also reduces measurably the resiliency and natural drapability of such base. Some attempts have been made to modify the conventional adhesive compositions to compensate for these deficiencies and/or to devise improved adhesives but in most cases the desired objectives have not been achieved.